In this October 21, 2015, file photo, a young man rides a hoverboard along a Manhattan street toward the Empire State Building in New York. More than 500,000 hoverboards are being recalled after reports that they can burst into flames. The Consumer Product Safety Commission said Wednesday, July 6, 2016, it has received 99 reports of battery packs in the two-wheel motorized scooters catching fire or exploding that causing burns or property damage. The recalled hoverboards were made by eight companies. (Photo by Kathy Willens/AP Photo)

A South China Tiger cub meets public at Guangzhou Zoo on June 22, 2017 in Guangzhou, Guangdong Province of China. Guangzhou Zoo boasts of the successful breeding of South China Tiger cub after 15 years. (Photo by VCG/VCG via Getty Images)

Two keepers at the Australian Reptile Park in New South Wales struggle with Leonardo, an alligator snapping turtle weighing 45 kilos at the park in Gosford, NSW 2 July 2015. The 50cm long Leonardo – who was smuggled illegally into Australia and found in a Sydney sewer in November 2000 – was removed from his tank for an annual health check. And as a gesture to onlooking press photographers demonstrated his strength by snapping a piece of bamboo in half. (Photo by EPA/HO)

An airplane house is pictured in the village of Miziara, northern Lebanon May 12, 2015. Miziara prides itself on building residential homes that resemble ancient Greek temples and Egyptian ruins, one is even built in the shape of an Airbus A380. (Photo by Aziz Taher/Reuters)

A group of young men use a selfie stick to take a picture of themselves in shallow waters known as the first cataract of the River Nile outside Khartoum, Sudan, May 22, 2015. In Sudan, which faces insurgences in the western region of Darfur and along its border with breakaway South Sudan, as well as double-digit inflation and high unemployment, life goes on for young people in the capital Khartoum. (Photo by Mohamed Nureldin Abdallah/Reuters)

Elvis Presley tribute artist Bruce Stewart (L) of Georgian Bay, Ontario passes Lorenz Francke of Scarborough, Ontario during the four-day Collingwood Elvis Festival in Collingwood, Ontario July 25, 2015. Featuring over 120 Elvis tribute artists, it is the world's largest Elvis festival and last year hosted 30,000 visitors. (Photo by Chris Helgren/Reuters)

Honorable Mention: “The Storm”. During I was taking photo with my nephew, the storm came and I caught this beautiful moment. Photo location: Kocaeli, Turkey. (Photo and caption by Aytül Akbaş/National Geographic Photo Contest)

Handout photo dated March 20, 2015 issued by Chester Zoo of lemurs looking at the eclipse over Chester Zoo. (Photo by Steve Rawlins/PA Wire/Chester Zoo)